Amusement rides known as “bumper cars” have been known and enjoyed for many years. (For example, certain models in the past were known as “Dodgem Cars” and “Glidabouts.”) A modern bumper car is a self-propelled, steerable vehicle usually intended to carry one or two riders around in an arena or the like without having to confine the vehicles to a track. The vehicles are individually equipped with compliant but resilient shock-absorbing structures (“bumpers”), mounted usually around the periphery of the vehicle, that allow the bumper cars to engage in collisions and the like without injury to the riders or damage to the cars, and without tipping the cars over. An exemplary type of bumper is disclosed in U.S. Pat. No. 5,516,169 to Falk et al., incorporated herein by reference. Whereas most types of conventional bumper cars are electrically powered, some are powered by small gasoline engines.
Most conventional electrically powered bumper cars are “externally” powered, i.e., powered by electrical current supplied to the bumper cars from a stationary source such an electrified floor or electrified floor and ceiling. An exemplary electrified floor is disclosed in U.S. Pat. No. 6,581,350 to Dean, incorporated herein by reference. In the '350 patent, direct-current electrical power is conducted from the floor to the cars via electrical pickups (“shoes” or “brushes”) beneath the cars that remain in sliding contact with the floor as the cars are being driven around on the floor.
One type of conventional externally powered bumper car comprises a frame to which are mounted the bumpers and a body including a seat for the rider. Also mounted to the frame, below the level of the seat, are driving wheels and stabilizing wheels (e.g., caster wheels). The driving wheels move the bumper car around the floor while the stabilizing wheels stabilize the car relative to the floor. Also mounted to the frame is a DC electric motor that runs continuously while the bumper car is being driven. Power from the motor is selectively delivered to the driving wheels via respective hydrostatic transmissions. The respective amounts of driving power delivered by the transmissions to the wheels are individually controlled by mechanisms, such as respective control levers, that are coupled to the transmissions, mounted to the frame, and manipulated by the rider. The rider steers the car by selectively applying, via the control levers gripped by the rider's hands, driving power to each driving wheel. In this type of bumper car, the manner in which driving power produced by the motor is delivered to the driving wheels is mechanically inefficient. The inefficiency is masked because the bumper car can draw as much current as it ever needs from the conductive floor. But, on the other hand, the bumper car can only be operated on a conductive floor, which imposes limitations and additional costs on use of the bumper car.
Another type of conventional bumper car is similar to the type summarized above, except that the electric motor is replaced with a gasoline motor. Use of a gasoline motor allows the bumper car to be operated on a non-electrified surface, but the mechanical inefficiencies are still present.
Other conventional bumper cars are configured for operation on a non-electrified surface by supplying electrical current from a battery mounted on and carried by the car. Unfortunately, to date, battery power for bumper cars has been disappointing for any of several reasons, as summarized below.
One conventional type of battery-powered bumper car utilizes a DC motor coupled via a gear box and chain-drive to a drive wheel. Steering is achieved by turning, via a first control, the entire mechanism of motor, gear box, and drive wheel. Motion and braking of the bumper car is achieved by manipulating a second control that turns the motor on and off. As noted above, normal use of a bumper car is characterized by a large number of rapidly executed starts, stops, directional maneuvers, and “bumps” into other bumper cars and walls. Driving the bumper car into a stationary wall or into another car can cause an abrupt stall (halt in rotation) of the motor even though power is still being delivered to the motor. At the moment of a stall, the motional emf of the motor drops to substantially zero, which causes the motor to draw a very large current (surge current) that is limited only by the inductance and resistance of the motor windings. Draw of surge current also occurs during starts of the bumper car from a stopped position and during rapid transitions from forward to reverse and vice versa. The large number of such draws of surge current accompanying normal use of the bumper car causes rapid battery drain (and if prolonged can cause overheating and failure of the motor). Consequently, the bumper car must be taken out of service frequently for recharging of the battery. Also, the manner of coupling the motor to the drive wheel is mechanically inefficient, and the steering mechanism in this type of bumper car is incapable of executing 360° spins “on a dime,” as currently desired in bumper-car rides.
Another type of conventional battery-powered bumper car comprises a small DC motor to which are coupled two gear boxes. Each gear box drives a respective drive wheel via a respective drive belt or chain. Forward, reverse, and steering motions of the car are achieved by manipulation of controls coupled to the gear boxes. In the course of driving the bumper car in rapid start, stop, and reverse maneuvers, surge current being delivered to the motor is reduced by use of hydraulic motion limiters in the controls. The motion limiters impose limits on the rate at which the rider can change motion of the car (e.g., impose a time delay in shifting from forward to reverse). This mechanism is complicated and inherently reduces the responsiveness of the car. Hence, this mechanism is used mainly on small, low-mass bumper cars intended to be ridden by very light-weight riders (namely, small children). Loads imposed by larger and heavier riders result in unacceptable rates of battery drain and render the bumper cars too unresponsive for acceptance by older children and adult riders.
Therefore, there is a need for bumper cars that are internally electrically powered while exhibiting an acceptable operational life of the portable source of electrical power carried by each car, without causing any significant detriment to the maneuverability and other performance features that riders expect from such amusement rides.